MTB and FCC with ASMA in SAP SFTP Adapter

In the Advantco Adapter we were able to pull fixed length files where the last field is mostly blank.We were using FCC and had ASMA enabled to retain the source filename as that was used by Dynamic Config in some UDF.

Now when we switched to SAP SFTP Adapter and configured with FCC and ASMA all files are pulled but they need all the fixed length parameters. The files which were having the last field as blank stopped working.

We are also trying to use MTB but even though it picks up the files with Source Name(ASMA still enabled) it adds a RecordSet to it thus the mapping fails.

We are not in a position to make too many changes in mapping. How do we fix either the FCC to pull the files with last field as blank or using MTB and remove the extra Record Set it is generating